Year: 2026
Type: article
Abstract: We present the results from a detailed study of the fragmentation dynamics of CS22+ and CS23+, formed in intense femtosecond soft x-ray pulses above the sulfur 2p edge, primarily through single core photoionization from the S 2p site, and subsequent Auger-Meitner decay(s). By combining three-dimensional velocity map imaging with covariance analysis, we determine the relative momenta of the ions produced in each two- and three-body fragmentation channel, at significantly higher ion count rates than conventional coincidence measurements. We shed new light on the wide range of fragmentation channels observed from the CS2 dication and trication, including channels that involve ionization-induced bond formation and fragmentations producing undetected neutral cofragments. In the latter case, a "native frames" approach is used to isolate contributions from concerted and sequential fragmentations and extract dynamical information about each step of a concerted fragmentation process. While dications often fragment sequentially, the trication is dominated by concerted fragmentation. The main trication fragmentation channel into S+ + C+ + S+ can be well-approximated by classical Coulombic simulations of the ground-state geometry distribution, reflecting both the nature of the trication potential energy surface and the rapid multiple ionization prior to substantial structural dynamics. This study demonstrates ways in which fundamental insights into the fragmentation dynamics of polycations following x-ray ionization may be extracted, which will be beneficial to future studies that employ time-resolved x-ray Coulomb explosion imaging to study ultrafast photochemistry.
Source: The Journal of Chemical Physics
DOI: 10.1063/5.0304278
Authors: Felix Allum, Chow-shing Lam, Benjamin Erk, Hubertus Bromberger, Philip H. Bucksbaum, Mathew Britton, Michael Burt, Nagitha Ekanayake, Ian Gabalski, Diksha Garg, Eva Gougoula, David Heathcote, Andrew J. Howard, Paul Hockett, David M. P. Holland, Sonu Kumar, Jason W. L. Lee, Joseph McManus, Jochen Mikosch, Dennis Milešević, Russell S. Minns, Christina C. Papadopoulou, Christopher Passow, Weronika O. Razmus, Anja Röder, Daniel Rolles, Arnaud Rouzée, Michael S. Schuurman, Alcides Simao, Albert Stolow, Atia-Tul Noor, James Unwin, Claire Vallance, Tiffany Walmsley, Mark Brouard, Ruaridh Forbes
Institutions: Deutsches Elektronen-Synchrotron DESY, SLAC National Accelerator Laboratory, Linac Coherent Light Source, University of Oxford, Stanford University, Trent University, University of California, Davis, National Research Council Canada, Daresbury Laboratory, Universität Hamburg, University of Kassel, University of Southampton, Max-Born-Institute for Nonlinear Optics and Short Pulse Spectroscopy, Kansas State University, University of Ottawa, Ruhr University Bochum
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, U.S. Department of Energy, Alexander von Humboldt-Stiftung, CALIPSOplus, Leverhulme Trust, University of Southampton, Bundesministerium für Bildung und Forschung, Max-Planck-Gesellschaft, Helmholtz Association, Office of Science, National Defense Science and Engineering Graduate, Engineering and Physical Sciences Research Council, Science and Technology Facilities Council, Jesus College, University of Cambridge, Jesus College, University of Oxford, European Research Council, Deutsches Elektronen-Synchrotron, Horizon 2020, Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division, SLAC National Accelerator Laboratory, HORIZON EUROPE European Research Council
Awards: G1077140421, G1229526393, G1286251239, G1797787269, G1815137805, G222768804, G2371548206, G2558280086, G2573442069, G262532246, Ultrafast Photochemical Dynamics in Complex Environments, STRUCTURE AND DYNAMICS OF ATOMS, IONS, MOLECULES AND SURFACES, G2978581158, G303061748, G3125155272, G333714909, G3474494657, G3530777102, G3826261775, G4235786860, G4336652674, Verbundprojekt: FSP 301 - FLASH: Nanoskopische Systeme. Teilprojekt 1.1: Universelle Experimentierkammer für Streuexperimente mit kohärenten Femtosekunden-Röntgenpulsen Multi Purpose Coherent Scattering Chamber for FLASH and XFEL 'MPscatt'., Verbundprojekt FSP 302 - Freie-Elektronen-Laser: Nanoskopische Systeme. Teilprojekt 4: Dynamik einzelner Nanoteilchen in Femtosekunden-Zeitlupe - Filmen mit ultrakurzen Röntgen-Doppelpulsen., G495301720, G498139845, G516729603, G5349887929, Imaging Chemical Dynamics with Ultrafast Laser Spectroscopy, G5570207115, G5648016710, G585716984, G5996689310, G6033966476, G6550344761, G6823224962, ATOMIC PHYSICS WITH HIGHLY CHARGED IONS, G7283024673, G7331630580, Verbundprojekt: FSP 301 - FLASH: Nanoskopische Systeme. Teilprojekt 1.2: Universelle Experimentierkammer für Streuexperimente mit kohärenten Femtosekunden-Röntgenpulsen Multi Purpose Coherent Scattering Chamber for FLASH and XFEL 'MPscatt'., G8382000481, G8499968185, Verbundprojekt 05K2016 - Nanoteilchenstruktur: Hochaufgelöste Struktur und Dynamik einzelner Nanoteilchen. Teilprojekt 1., G8726098666, G911061179, G969889393, STRUCTURE AND DYNAMICS OF ATOMS, IONS, MOLECULES AND SURFACES
OpenAlex ID: W7119532002